HENKE'S MED-MATH
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Ch. 1 — Multiplying Whole Numbers
1. A 62-year-old patient is prescribed an oral antibiotic: 250 mg
tablets, take 3 tablets now for an initial loading dose. How
many milligrams will the patient receive with the three tablets?
A. 500 mg
B. 750 mg
C. 1,000 mg
D. 625 mg
Correct answer: B. 750 mg
Rationale — Correct (B): Multiply the tablet strength by the
number of tablets: 250 mg × 3 = 750 mg. This uses
,straightforward whole-number multiplication (Henke’s method:
align units, multiply numerators). Confirm units remain mg. The
result is a single, verifiable total dose (750 mg).
Rationale — A: 500 mg reflects 250 mg × 2 (omitted one
tablet). This error under-doses by one tablet.
Rationale — C: 1,000 mg reflects 250 mg × 4 (one extra tablet).
This error would give an overdose.
Rationale — D: 625 mg suggests an arithmetic or partial
multiplication error (250 × 2.5). Tablets are whole or scored —
check order before giving fractional tablets.
Teaching point: Multiply unit strength × number of units;
always keep units consistent.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Dividing Whole Numbers
2. Provider orders 900 mg of a medication. The medication is
available as 300 mg tablets. How many tablets should the nurse
administer?
A. 2 tablets
B. 3 tablets
C. 4 tablets
D. 3.5 tablets
Correct answer: B. 3 tablets
,Rationale — Correct (B): Divide ordered dose by tablet
strength: 900 mg ÷ 300 mg per tablet = 3 tablets. Units cancel
(mg ÷ mg → tablets). This is the ratio-proportion approach
recommended in Henke: (ordered / available) = number of
units.
Rationale — A: 2 tablets = 600 mg — underdoses by 300 mg.
Likely from incorrect division.
Rationale — C: 4 tablets = 1,200 mg — overdoses by 300 mg.
Likely from multiplying instead of dividing.
Rationale — D: 3.5 tablets = 1,050 mg — arises from misplacing
decimal or rounding incorrectly.
Teaching point: Use ordered ÷ strength to get number of
tablets; keep units mg/mg.
Citation: Buchholz, S. (2024). Henke’s Med-Math... Ch. 1.
Ch. 1 — Fractions (Multiplication of Fractions)
3. A pediatric patient should receive 2/3 of a 150 mg dose per
protocol. Calculate the milligrams the child will receive.
A. 50 mg
B. 75 mg
C. 100 mg
D. 125 mg
Correct answer: C. 100 mg
Rationale — Correct (C): Multiply fraction by total: (2/3) × 150
mg = 150 × 2 ÷ 3 = 300 ÷ 3 = 100 mg. Henke’s fraction
, multiplication: multiply numerator by total then divide by
denominator. Units remain mg.
Rationale — A: 50 mg equals (1/3) of 150 mg, likely using
wrong fraction.
Rationale — B: 75 mg equals (1/2) of 150 mg, representing a
half-dose error.
Rationale — D: 125 mg suggests incorrect arithmetic: perhaps
150 – 25 instead of proper fraction multiplication.
Teaching point: Multiply the total by the fraction
(numerator/denominator), maintain units.
Citation: Buchholz, S. (2024). Henke’s Med-Math... Ch. 1.
Ch. 1 — Decimals (Volume from Concentration)
4. The provider orders 1.25 mg of a drug that is supplied as 0.5
mg/mL solution. What volume (mL) should the nurse draw up?
A. 0.25 mL
B. 2.5 mL
C. 1.75 mL
D. 3.0 mL
Correct answer: B. 2.5 mL
Rationale — Correct (B): Convert using division: volume (mL) =
ordered dose ÷ concentration = 1.25 mg ÷ 0.5 mg/mL = 2.5 mL.
Units: mg ÷ (mg/mL) = mL. Use decimal division per Henke’s
guidance.
DOSAGE CALCULATION, PREPARATION
& ADMINISTRATION
10TH EDITION
• AUTHOR(S)SUSAN BUCHHOLZ
TEST BANK
Ch. 1 — Multiplying Whole Numbers
1. A 62-year-old patient is prescribed an oral antibiotic: 250 mg
tablets, take 3 tablets now for an initial loading dose. How
many milligrams will the patient receive with the three tablets?
A. 500 mg
B. 750 mg
C. 1,000 mg
D. 625 mg
Correct answer: B. 750 mg
Rationale — Correct (B): Multiply the tablet strength by the
number of tablets: 250 mg × 3 = 750 mg. This uses
,straightforward whole-number multiplication (Henke’s method:
align units, multiply numerators). Confirm units remain mg. The
result is a single, verifiable total dose (750 mg).
Rationale — A: 500 mg reflects 250 mg × 2 (omitted one
tablet). This error under-doses by one tablet.
Rationale — C: 1,000 mg reflects 250 mg × 4 (one extra tablet).
This error would give an overdose.
Rationale — D: 625 mg suggests an arithmetic or partial
multiplication error (250 × 2.5). Tablets are whole or scored —
check order before giving fractional tablets.
Teaching point: Multiply unit strength × number of units;
always keep units consistent.
Citation: Buchholz, S. (2024). Henke’s Med-Math: Dosage
Calculation, Preparation & Administration (10th ed.). Ch. 1.
Ch. 1 — Dividing Whole Numbers
2. Provider orders 900 mg of a medication. The medication is
available as 300 mg tablets. How many tablets should the nurse
administer?
A. 2 tablets
B. 3 tablets
C. 4 tablets
D. 3.5 tablets
Correct answer: B. 3 tablets
,Rationale — Correct (B): Divide ordered dose by tablet
strength: 900 mg ÷ 300 mg per tablet = 3 tablets. Units cancel
(mg ÷ mg → tablets). This is the ratio-proportion approach
recommended in Henke: (ordered / available) = number of
units.
Rationale — A: 2 tablets = 600 mg — underdoses by 300 mg.
Likely from incorrect division.
Rationale — C: 4 tablets = 1,200 mg — overdoses by 300 mg.
Likely from multiplying instead of dividing.
Rationale — D: 3.5 tablets = 1,050 mg — arises from misplacing
decimal or rounding incorrectly.
Teaching point: Use ordered ÷ strength to get number of
tablets; keep units mg/mg.
Citation: Buchholz, S. (2024). Henke’s Med-Math... Ch. 1.
Ch. 1 — Fractions (Multiplication of Fractions)
3. A pediatric patient should receive 2/3 of a 150 mg dose per
protocol. Calculate the milligrams the child will receive.
A. 50 mg
B. 75 mg
C. 100 mg
D. 125 mg
Correct answer: C. 100 mg
Rationale — Correct (C): Multiply fraction by total: (2/3) × 150
mg = 150 × 2 ÷ 3 = 300 ÷ 3 = 100 mg. Henke’s fraction
, multiplication: multiply numerator by total then divide by
denominator. Units remain mg.
Rationale — A: 50 mg equals (1/3) of 150 mg, likely using
wrong fraction.
Rationale — B: 75 mg equals (1/2) of 150 mg, representing a
half-dose error.
Rationale — D: 125 mg suggests incorrect arithmetic: perhaps
150 – 25 instead of proper fraction multiplication.
Teaching point: Multiply the total by the fraction
(numerator/denominator), maintain units.
Citation: Buchholz, S. (2024). Henke’s Med-Math... Ch. 1.
Ch. 1 — Decimals (Volume from Concentration)
4. The provider orders 1.25 mg of a drug that is supplied as 0.5
mg/mL solution. What volume (mL) should the nurse draw up?
A. 0.25 mL
B. 2.5 mL
C. 1.75 mL
D. 3.0 mL
Correct answer: B. 2.5 mL
Rationale — Correct (B): Convert using division: volume (mL) =
ordered dose ÷ concentration = 1.25 mg ÷ 0.5 mg/mL = 2.5 mL.
Units: mg ÷ (mg/mL) = mL. Use decimal division per Henke’s
guidance.
